Add explicit virtual default destructors

We need to silence the warning about this because Steinberg doesn't
declare their base class destructors as virtual (because of Windows ABI
compatibility issues). But we can still do it inside of yabridge to have
at least a bit more safety.

src/wine-host/bridges/common.cpp

@@ -57,8 +57,6 @@ HostBridge::HostBridge(MainContext& main_context,
       parent_pid_(parent_pid),
       watchdog_guard_(main_context.register_watchdog(*this)) {}
 
-HostBridge::~HostBridge() noexcept {}
-
 void HostBridge::handle_events() noexcept {
     MSG msg;
 

src/wine-host/bridges/common.h

@@ -37,7 +37,7 @@ class HostBridge {
                pid_t parent_pid);
 
    public:
-    virtual ~HostBridge() noexcept;
+    virtual ~HostBridge() noexcept = default;
 
     /**
      * If a plugin instance returns `true` here, then the event loop should not